Colorimetric detection of oxalate in aqueous solution by a pyrogallol red-based Cu2+ complex

Abstract

The pyrogallol red (PR)-based Cu²⁺ complex was proven to be an effective and selective colorimetric chemosensing ensemble for recognition of oxalate over other anions in a perfect aqueous solution. The addition of oxalate to the PR-Cu²⁺ complex resulted in a colour change from purple to orange colour due to the regeneration of PR by the chelation of oxalate with Cu²⁺ , while other anions did not induce any significant colour change. Moreover, it was revealed that no obvious interference was observed during the titrations with oxalate into each other anion. Therefore, the PR-Cu²⁺ complex can be used as a simple and practical colorimetric chemosensor for detecting oxalate.

Keywords: chemosensor; colorimetric detection; copper ion; oxalate; pyrogallol red.